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Plums, Magnum Bonum, Preserved
Magnum bonum and other fine plums may be boiled into a jam in the usual way, or preserved whole like apricots, or as follows. Take fine, ripe, sound fruit. Pare them, and in order to do this more easily throw them into boiling water for a minute. If they are not fully ripe, they will need to simmer gently for two or three minutes. Take a pound of sugar to each pound of fruit. Dissolve in a little water, skim carefully, and boil until it is almost candy height. Throw in the plums, and let them boil gently for a quarter of an hour. Lift them out carefully, strain the syrup over them, and let them lie for two days. Boil them again until they look quite clear, put them into jars, cover with the syrup, tie the jars up, and store in a cool, dry place. Time, three days. Boil the plums the last time about ten minutes.
This is a whole-fruit preserve made the slow way: the plums are candied gradually over three days so they stay intact and turn translucent rather than collapsing into jam. The instructions assume a cook who knows sugar boiling by eye, so a thermometer and a few notes help.
- The hinge: don't shorten the three daysThe two-day rest is what makes this work. Syrup penetrates the fruit slowly, so the plums firm up and clarify instead of shrivelling. Boil it all through in one session and you get skins in syrup.
- "Almost candy height"Old sugar-boiling degrees ran from thread through pearl, feather, ball and crack; "candy height" sits high on that scale and the original is genuinely imprecise. No single modern temperature can be fixed to it, so judge by the syrup coating the spoon heavily.
- Peeling by blanchingA minute in boiling water loosens the skins; slit each plum first and the skin slips off. Underripe fruit needs the longer two to three minutes, but past that the flesh begins to break down and will not hold its shape through the two boilings.
- Equal weightsA pound of sugar to a pound of fruit is the whole formula. That high sugar ratio is what preserves the plums, so reducing it changes the keeping quality, not just the sweetness.
- The stones stay inThe recipe pares the fruit but says nothing about stoning, and whole plums preserved this way keep their stones. Warn anyone at the table, or stone them through a slit in the side before blanching and accept slightly softer fruit.
- Jars and covers"Tie the jars up" means a paper or bladder cover tied with string — adequate in a cold larder, but it invites surface mould in a heated house. Use clean hot preserving jars, fill while the syrup is boiling hot, and seal properly.
- Choosing plumsMagnum Bonum is a large firm cooking plum. Any dense, slightly underripe cooking variety works — Victoria, damson-sized golden plums, Italian prune plums. Soft dessert plums will not survive the repeated boiling.
Magnum bonum is simply Latin for "great good", a nurseryman's boast attached to more than one large fruit and vegetable in the eighteenth and nineteenth centuries — there was a famous Magnum Bonum potato as well as the plum. The plum meant here is the big oval yellow English cooking plum, generally identified with the variety sold as Yellow Egg, prized for holding its shape rather than for eating raw. The recipe sits under a general heading of plum preserving because a Victorian household with a plum tree faced a glut in a matter of days and needed several methods: jam for quantity, bottling for convenience, and this slow candying for the fruit good enough to be shown off whole at dessert. The technique of repeated short boilings with long rests between them is the same one used for candied peel, angelica and preserved apricots, and it reflects a period when sugar was cheap enough to use pound for pound but cold storage was limited to ice houses and the commercial ice trade.